SUMMARY Taste buds contain a diversity of co-mingled cell types that perform distinct functions. Although the chemosensory cells have been studied quite extensively, we have limited understanding of cellular interactions within the bud including how taste cells establish and maintain specific innervation throughout life. This open question guides the design of experiments to continue our program of integrated molecular, cellular and functional approaches to the taste system. Cell types II and III are chemosensory, with each cell prominently sensitive to taste stimuli of one sub- modality (e.g.sweet). Taste bud cells die off and are replaced throughout life, while the nerve fibers that interdigitate between taste cells are relatively stable. How is appropriate connectivity orchestrated? For instance, individual Type II cells of the taste bud typically express one type of taste receptor (e.g. T1R1+T1R3) and respond functionally to ligands of one taste quality (e.g. ?sweet?). Afferent neurons also often respond best to one taste quality. Thus, ?sweet cells? are inferred to transmit signals preferentially to ?sweet fibers?. Yet, throughout life, Type II cells are replaced with a half-life of ?8 days. How do nerve fibers of a particular identity recognize and connect with newly formed taste bud cells of the corresponding chemosensitivity? Several families of synaptic recognition and adhesion proteins are currently under investigation that guide synaptogenesis in the brain during development and then stabilize synapses in the adult. Our preliminary RNAseq data have yielded candidate pre- and post- synaptic pairs of proteins in taste cells and taste neurons. We will conduct a detailed exploration of the proteins that mediate the selective pairing of taste cells and nerves. Second, there is growing appreciation that in the brain, glia are intimately associated with synapses, both anatomically and functionally. Taste buds have their own ?glia?, the Type I cells that ensheath chemosensory cells. Although these cells are the most numerous, we do not know if they are passive supporting cells or active participants in producing the sensory output of the bud. Do chemosensory cell, afferent fibers and Type I cells cooperate functionally in the manner of central ?tripartite synapses?? Using a genetically encoded Calcium indicator, we will test whether Type I cells are able to sense the activation of the chemosensory cells that they ensheath, as perisynaptic glia are known to do. We will test if Type I cells promote the formation of new synapses between chemosensory cells and afferent fibers as synaptic astrocytes are known to do. This application employs state of the art transcriptomic analyses and high resolution confocal functional imaging to examine how taste cells communicate with afferent neurons throughout life, and how this communication may be modulated and shaped under different physiological conditions.